Gassantoda Castle

Gassantoda is a ruined hilltop castle in Yasugi, Shimane Prefecture, that spreads across the ridges and valleys of Mount Gassan, standing 180 meters above the Hirose River. The site consists of several fortified levels connected by stone steps and pathways that offer wide views over the surrounding landscape.

The fortress was built in 1396 and served as the main seat of the Amago clan until 1566, when it fell to the Mori clan after a long siege. Following the conquest, the site was gradually abandoned and never again used for military purposes.

The fortress takes its name from Mount Gassan, which appears in regional records as an important landmark for travelers and merchants. The ruins today still show the typical construction of Japanese mountain fortresses with terraced defense lines spreading across multiple peaks.

The ruins can be reached by taking an hour-long bus from Yasugi Station to the Gassan-Iriguchi stop, followed by a 40-minute uphill walk. The path leads over narrow trails and uneven ground, so sturdy footwear and reasonable fitness are necessary.

Amago Tsunehisa initially captured the fortress through a clever ruse by disguising his soldiers as festival dancers, leading them unnoticed into the interior. This strategy is mentioned in local chronicles as one of the most ingenious military maneuvers of the Japanese feudal era.

Location: Yasugi

Location: Shimane Prefecture

Inception: 1396

Part of: 100 Fine Castles of Japan

Website: https://yasugi-kankou.com/en/spot/gassantoda-castle

GPS coordinates: 35.36085,133.18527

Latest update: December 13, 2025 18:21